1. Make the broth: In a large stock pot, combine 2½ quarts of water with the prosciutto hock, Parmesan rind, bay leaves, coriander and a large pinch of salt. Bring to a simmer and cook for 30 minutes.

2. Shuck the fresh peas and reserve the pods. (You'll get about 3½ cups peas.) Rinse the pods, peas and pea shoots separately in cold water, then drain. Add the pea pods to the simmering broth.

3. In a large pot, heat the olive oil over medium heat. Add the pancetta and cook, stirring occasionally, until it sizzles and begins to crisp, about 4 minutes. Stir in the peas and a pinch of salt and increase the heat to medium-high. Cook for 2 minutes until the peas soften slightly, then stir in the lettuce, a quarter of the pea shoots and 1 cup of the broth. Turn the heat down to medium and continue to simmer, stirring frequently.

4. Place the rest of the pea shoots in a blender and carefully add the remaining broth through a fine-mesh strainer, discarding the pea pods and rinds. Blend at high speed until the mixture is smooth. Stir the pureed broth into the pancetta-pea mixture and cook until the peas and lettuce are soft, about 7 to 10 minutes. Season to taste with salt and pepper.

5. To serve, ladle the soup into 4 bowls, top each with a few slices of ricotta salata, a generous drizzle of olive oil and a small pinch of black pepper.